In the widely used keg tapping systems of the type to which the present invention generally relates, each keg is fitted with a keg unit that is seated in its bung hole and comprises normally closed valves that are opened by installation on the keg of a coupler or tapping unit. The keg installation defines an upwardly opening well in which the coupler or tapping unit is receivable, and the bottom of the well is defined by an annular gas valve seat, a concentric annular gas valve which is biased upwardly for engagement with the gas valve seat and which itself defines a liquid valve seat, and a central poppet-like liquid valve that is biased upwardly for engagement with the liquid valve seat. When the keg is tapped, beer flows up to the liquid valve through a siphon tube which extends down to near the bottom of the keg, being forced up the siphon tube by pressure gas filled into the keg past the open gas valve.
A coupler or tapping unit to be coupled to the keg conventionally has a substantially annular outer body member that is received in the well and makes a bayonet connection with lugs on the keg that project radially into the well near its top. When that bayonet connection is established, a radially inner body member of the coupler is moved down to open the gas and liquid valves in the keg and thus communicate the interior of the keg with gas and liquid passages in the coupler.
In a tavern installation, the liquid passage in the coupler is more or less permanently connected with a duct that leads to a beer tap at the bar, while the gas passage in the coupler is connected with a source of pressure gas (usually a bottle of compressed carbon dioxide) from which the interior of the keg is pressurized. The tavern installation coupler includes a valve in its gas passage that is closed when the inner member is in its raised position and is opened when the inner member is moved down to open the gas and liquid valves in the keg. This valve in the coupler unit gas passage prevents loss of pressure gas from the source thereof during the time that the coupler is being transferred from one keg to another.
In the usual tavern coupler, the inlet to the gas passage comprises a spout-like nipple that is formed on the coupler body and projects laterally to one side of it, while the liquid passage opens to a concentric upwardly projecting nipple on the top of the coupler body. Normally, the gas hose and the duct that leads to the beer tap are respectively connected to these nipples.
When keg beer is purchased for consumption at a party or picnic, it is delivered in a keg having a valve installation identical to the one in a keg delivered to a tavern, and the purchaser must therefore arrange for use of a coupler or tapping unit in order to be able to dispense the beer from the keg. On such an occasion it is obviously impractical to provide a bottle of pressure gas, along with the plumbing and pressure control valves that are normally incorporated in the pressure gas system of a tavern installation, and therefore the keg is pressurized by means of a hand pump.
It has been generally customary for the purchaser of keg beer for occasional use to rent a coupler for the occasion, usually from the dealer from whom the keg beer was purchased. Heretofore the so-called picnic couplers that have been made available for this purpose have been tavern units that were more or less modified for connection with a hand pump.
In some cases the hand pump had a rigid threaded connection directly to the gas line nipple on the coupler body, and it projected sidewardly from the coupler, coaxially with that nipple. Such an installation, although relatively convenient and inexpensive, had the significant disadvantage that the pump acted as a lever by which very large upward bending forces could be exerted upon the bayonet connection lugs that projected into the coupler well in the keg. It often happened that these lugs were bent up during use of a picnic coupler. Sometimes their deformation was not noticed when the keg was returned to the brewery, and the defective keg was unwittingly delivered to a purchaser who found himself unable to tap it.
To avoid the possibility of such damage to cooperage some picnic couplers have been furnished with a separate hand pump that was mounted on the tapped keg by means of a special bracket and was connected to the gas passage nipple of the coupler unit by means of a hose or the like. Provision of such an assembly of course involved the cost of the bracket and the hose in addition to the rather substantial cost of the hand pump and the coupler unit.
A third type of heretofore conventional picnic coupler, likewise relatively expensive, was one wherein an elongated device that projected coaxially up from the top of the coupler comprised a hand pump that was more or less integrated with a laterally projecting liquid dispensing outlet near its top. Although offering less possibility for damaging the keg lugs than the laterally projecting pump, substantial lug-deforming leverage could nevertheless be exerted at the upper end of this vertical pump, and the location and orientation of the pump were such that it was somewhat inconvenient to operate.
Whatever its functional advantages and disadvantages, all of this prior picnic coupler equipment posed an economic problem which has always been significant but which has become increasingly severe in recent years. The modified tavern coupler and the hand pump associated with it constituted a package which cost substantially more than the amount of any deposit on it that users could reasonably be expected to pay. Knowing that the equipment was worth more than the deposit, users have often deliberately failed to return the equipment and forfeited the deposit.
Since a beer depot cannot sell keg beer if it requires the purchaser to pay an extremely high deposit on picnic coupler equipment, and it cannot afford to sell keg beer if there are going to be losses from time to time on unreturned equipment, many beer depots have simply stopped selling keg beer.
In addition to the obvious economic detriment to beer depots and breweries, the lack of an inexpensive but satisfactory picnic coupler has resulted in some loss of what is, for many, one of the genuine pleasures of life. Thus the problems posed by the need for a satisfactory picnic coupler have such widespread and substantial impact that if there had been any obvious solution to them, that solution would undoubtedly have come forth long ago.